Abstract
Microbes in pit mud (PM) are vital for the solid-state fermentation of strong-flavour baijiu (SFB), influencing the flavour and quality of SFB through metabolic activity. This study aimed to elucidate the differences in microbes and metabolites in PM at varying cellar ages and spatial positions. Microbes and metabolites in PM exhibited significant spatiotemporal variations, with temporal heterogeneity being more pronounced than spatial heterogeneity. Fourteen and 21 dominant genera were identified in 7-year and 50-year PM, respectively. Redundancy analysis suggested that pH, lactic acid, humus, and acetic acid drive microbial community succession. A total of 255 metabolites were identified, with acids, carbohydrates, and alcohols being the most prevalent. Significant positive correlations between the biomarkers and the main differential metabolites were revealed. Structural equation modeling demonstrated significant correlations between physicochemical factors, biomarkers, and the main differential metabolites. This study provides a foundation for future modifications of the quality and flavour of SFB.